River of Fundament is a beast of a film. The latest from Matthew Barney, the heralded filmmaker/visual artist behind The Cremaster Cycle and Drawing Restraint, is an avant-garde epic that lavishes imagery of natural grandeur and excess of every color. The Hollywood Reporter's review rightfully calls the film "willfully obscure and scatologically extreme." It's a movie that splashes across the screen with a tidal wave of thematic concepts, some better explored than others: life, death, philosophy, religion, history, mythology, politics, America, industry, urban development, societal construct, and, most abrasively, bodily functions. The local multiplex doesn't have room for The River of Fundament -- for a multitude of reasons.

Barney's film is a six-hour opera loosely adapted from Norman Mailer's critically panned novel Ancient Evenings. The film chronicles the author's quest to continually resurrect himself, by wading through the "River of Feces," communicating with Egyptian gods and being literally born again from the belly of a cow. Along the way a number of famous faces pop up to question, echo, complicate and add to the texture of River of Fundament. Some play themselves; others are knee-deep in fictionalized roles. The Academy Award-worthy talent that Barney has wrangled for his film is astounding. What they're asked to do, even more so.

Here's a look at the motley crew assembled by Barney for a film that will be stirring up the art world for years to come.

Paul Giamatti: The Oscar-nominated actor appears in the first act of the film as Ptah-nem-hotep, the current Pharaoh of...Egypt? New York? The world? Hard to say, but his character has affection for the soul of Mailer. Giamatti is clearly a king -- throughout his time in the film he's being given head rubs, foot massages and hand jobs, but he's still envious of the resurrected author's access to the gods. Giamatti has a great scene where he talks about the essence of fecal matter and magic. Not exactly the wine-infused philosophy of Sideways, but close.

Maggie Gyllenhaal: Another Oscar nominee, another jaw-dropping, this-would-never-happen-in-Hollywood-in-a-million-years moment. Gyllenhaal has less to do than Giamatti in River of Fundament, though the lengths she goes to are more extreme. The actress plays an adult version of Hathfertiti, Mailer's medium for rebirth. After briefly appearing in a scene where she milks her own breast, Hathfertiti sits down with the ancient Pharaoh Usermare to reveal their kinship and state her case for continually bringing Mailer back to life. What could be a simple conversation is Gyllenhaal sing-speaking to a decaying old man while naked extras dance, spray water out of their orifices and play each other's butts like trumpets. Quick insert shots to a decaying pig corpse from the wake dinner remind the audience that it must reek in the room. If there was an Oscar given for "Most Ecstatic Chaos Endured During the Filming of a Movie," it would go to Gyllenhaal.

Ellen Burstyn: The 81-year-old actress (who adds even more cred to the film, having been nominated for an Oscar six times, with one win) appears as the oldest version of Hathfertiti. Barney protects his matriarch from provocative stunts: We follow Burstyn to the end of Hathfertiti's journey, a deep sleep that cuts off Mailer's resurrection rights. The director does intercut her bedtime footage with shots of a sliced-open cow carcass filling Mailer's brownstone with blood, so that makes up for it.

Aimee Mullins: The real-life amputee and Paralympic runner (and Alexander McQueen fashion model) appears in a double role: First, as a fecal matter-covered "Ka" spirit that leads Mailer through his journey, and then as Isis, a police detective investigating the murder of her brother, Osiris. She finds him resurrected as a Chrysler Imperial, only to see the car melted down. She also gives birth to a bird in the backseat of a car, which we see in all its glory.

Elaine Stritch: The stage and screen veteran delivers a eulogy to the late Mailer, praising Ancient Evenings while damning the world's misunderstanding of the text. Her delivery of the monologue is both tender and biting. No perversity required.

Dick Cavett, author Jeffrey Eugenides, Fran Lebowitz, Cinqué Lee, Larry Holmes,avant-garde filmmaker Jonas Mekas,porn star Adrianna Nicole, Salman Rushdie, James Toback and artist Lawrence Weiner: A "That guy!" selection of New York City's intelligentsia gathers in Mailer's apartment to send off their friend in style. Little do they know his spirit has just emerged from a river of poop that flows beneath them!

Deborah Harry: The Blondie frontwoman is also among the attendees of Mailer's wake, but she does a little singing. How could you not throw her a song?

John Buffalo Mailer: Mailer's actual son appears as the first restored version of the author's spirit.

Milford Graves: The legendary jazz drummer appears as the second incarnation of Norman Mailer (meaning, Barney tucked him into an gutted cow corpse and had him to claw his way out), who spends most of his time hanging by the River of Feces, banging on drums. As one does.

Herbert Perry and Eugene Perry: The acclaimed twin opera stars appear as two sides of the Egyptian god Set, who slays a Harry Houdini-looking Osiris by driving his car off a bridge. It's unclear which of the brothers also takes a pee on a block of mineral while surrounded by the guests of Mailer's wake, but in the end, they're both Set.

Ryan Robinson: The young YouTube star went viral a few years ago for his human beatboxing. Little did he realize that Internet fame would lead him to a Barney film in which he spits out percussive beats as a woman spews liquid excrement from the wrong hole. To be fair, there's symbolic value: After being valued by many of the characters, fecal matter is a suddenly violent, terrifying material. Accompanied by beatboxing.

Bobbi Starr: Late into River of Fundament's third act, a pregnant woman removes her glass eye and gently places it into another pregnant woman's anus. The recipient of the gift is Bobbi Starr, whom Barney describes in a New York Times interview as being "really easy to direct. She’s a classical oboist. And one of the most famous anal actresses in the adult film business."

River of Fundament played at the Brooklyn Academy of Music this past weekend as part of a proposed world tour of the film.